1. Field of the Invention
The present invention relates to a pluggable optical transceiver used in an arrangement that, inserting into a rail or a cage prepared on a host board, the electrical plug implemented in a rear end thereof mates with the electrical connector set in the deep end of the rail or the connector.
2. Related Prior Art
Various prior documents have been disclosed a pluggable system between the host equipment and the optical transceiver, such as US-2004081418A, US-20070133930A and US-20070110374A. The installation of the pluggable transceiver on the host device was accomplished by setting the pluggable transceiver in the cage or the rail they were prepared in the host device. The optical transceiver provided an electrical plug in the end thereof, while, the cage or the rail installed an electrical connector in the deep end thereof. The communication path between the transceiver and the host device, or the path for supplying the electrical power form the host device to the transceiver, was established by mating the plug with the connector.
As the amount of the communication increases, the performance necessary to the optical transceiver has steadily and rapidly risen. The conventional transceiver disclosed the prior applications above reached the transmission speed to 10 Gbps; while, recent request in the field has raised the speed over 10 Gbps. One solution is proposed, in which four (4) signals each having the transmission speed of 10 Gbps and a specific wavelength different from each other are transmitted in single fiber, which realizes the total communication capacity of 40 Gbps. In another proposal, four signals with the transmission speed of 25 Gbps are wavelength multiplexed to realize the total capacity of 100 Gbps.
Even in new standards, the communication between the transceiver and the host device is limited in the speed thereof to 10 Gbps because of the electrical mismatching of the transmission impedance at the electrical connector and the plug. Therefore, it is indispensable to transmit a plurality of electrical signals with the speed of 10 Gbps. In the standard of the 100 Gbps transmission mentioned above, 10 electrical signals are necessary to be transmitted or received between the transceiver and the host device. These 10 signals (10×10 Gbps) are multiplexed to four faster electrical signals each showing the speed of 25 Gbps (4×25 Gbps) and optically transmitted in the optical fiber as the wavelength division multiplexed (WDM) signals. For the receiver, 4×25 Gbps optical signals are received and electrically de-multiplexed to 10×10 Gbps signals which are transmitted to the host device.
Accordingly, the electrical connector and the plug are necessary to provide at least 20 electrodes for both operations of the transmission and the reception. Moreover, greater power consumption is necessary for the electronic components in the transceiver to process such high speed signals and more ground patterns are also necessary to suppress the waveform degradation. These critical conditions result in the increase of the number of the electrode in the connector and the plug. The new standards relating to the 100 Gbps transmission has ruled the number of the electrode is 148 pins.
In another aspect of the electronic equipment, because a smaller sized housing is permanently requested in the field, it is not allowable solution to enlarge the size of the housing as the increase of the number of the electrode. The standard of the 100 Gbps transmission has defined the width of the housing to be only 72 mm. When 148 pins mentioned above are set within this width, the pitch of the electrode becomes only 0.8 mm. Therefore, a new mechanism is necessary to secure the reliable engagement between the multi-pinned connector and the plug.